Which gland controls the functioning of other endocrine glands?

Correct Answer: D

Rationale: The pituitary gland, located at the brain's base, is the master gland, orchestrating other endocrine glands via hormone secretion. Its anterior lobe releases hormones like TSH (thyroid-stimulating hormone) to regulate the thyroid's metabolism control, ACTH (adrenocorticotropic hormone) for adrenal cortisol production, and gonadotropins (FSH, LH) for ovarian and testicular function. The posterior lobe secretes oxytocin and vasopressin, influencing reproduction and water balance. This pea-sized gland, about one-third inch wide, integrates hypothalamic signals, amplifying its reach across the endocrine system. The thyroid governs metabolism but doesn't control other glands. The pineal gland, producing melatonin for sleep, lacks broad regulatory power. Adrenal glands manage stress and metabolism via cortisol and adrenaline, but they're subordinate to pituitary signals. The pituitary's dual-lobe structure adenohypophysis and neurohypophysis enables its extensive influence, evidenced by disorders like hypopituitarism affecting multiple systems. Endocrine physiology positions it as the central coordinator, distinct from glands with narrower roles.

Correct Answer: C

Rationale: The hypodermis, or subcutaneous layer, is mainly adipose tissue, storing fat for insulation and energy, cushioning underlying structures. Epidermis is epithelial, dermis is connective with glands/vessels, and stratum granulosum is an epidermal sublayer, none fat-dominated. Hypodermis's fat content, per skin structure, makes 'c' correct.

Correct Answer: B

Rationale: Parathyroid hormone (PTH) increases blood calcium by stimulating osteoclasts, kidney reabsorption, and vitamin D activation, countering low levels. Calcitonin lowers calcium, depositing it in bones. Estrogen and testosterone affect bone density, not directly calcium. PTH's regulatory role, per endocrinology, makes 'b' correct.

Correct Answer: A

Rationale: Sutures are immovable, fibrous joints connecting skull bones (e.g., coronal), locking them post-growth. Fontanels are infant soft spots, closing to sutures. Joint is broad, but suture is specific. Ligaments connect bones elsewhere. Sutures' cranial role, per anatomy, makes 'a' correct.

Correct Answer: B

Rationale: The sternum connects ribs via costal cartilage, supporting the thoracic cavity and protecting heart/lungs. Spinal cord is vertebral, breathing is secondary (diaphragm-driven), skull support is cranial. Sternum's thoracic role, per anatomy, makes 'b' correct.